Frank Hills

Regulated expression of signal transducer and activator of transcription, Stat5, and its enhancement of PRL expression in human endometrial stromal cells in vitro.

Differentiation of human endometrium during the secretory phase of the menstrual cycle is characterized by expression of a variety of genes implicated in the establishment and maintenance of pregnancy. An increased abundance of signal transducers and activators of transcription (Stats) in the secretory phase suggests Stat5 as a component of the differentiation of endometrium in response to ovarian hormone stimulation in vivo. Decidualization is initiated in a subset of endometrial stromal cells (ESC) in vivo during the secretory phase, but it is unclear whether regulated expression of Stat5 is a feature of these cells. Here, therefore, the abundance and subcellular distribution of Stat5 in ESC after a decidualization stimulus of cAMP plus medroxyprogesterone acetate (MPA) has been investigated in vitro. Western blotting revealed an increase in the apparent abundance of Stat5a and Stat5b, in the cytosolic and nuclear fractions, at 2, 3, and 4 d after stimulation. The potential functional relevance of this increase in Stat5 is suggested by the ability of transiently transfected Stat5a or Stat5b to significantly enhance the response of the decidual PRL promoter to cAMP/MPA and attenuation of the response to cAMP/MPA by dominant negative Stat5. Recent evidence suggests endometrial differentiation, including PRL production, as a possible target of antiphospholipid antibodies (aPL) prevalent in recurrent miscarriage. Monoclonal antibody, ID2, which has similar reactivity as human aPL, significantly decreased the apparent abundance of nuclear Stat5b in response to cAMP/MPA and was associated with decreased decidual PRL promoter activation and PRL secretion. Regulated expression of Stat5 is therefore a component of decidual differentiation of human ESC and contributes significantly to activation of the decidual PRL promoter. Alteration of this process by an aPL component suggests decidual differentiation as a potential clinical target in recurrent early miscarriages.

Progesterone represses interleukin-8 and cyclo-oxygenase-2 in human lower segment fibroblast cells and amnion epithelial cells.

Abstract Labor is preceded by cervical ripening through upregulation of interleukin (IL)-1β, IL-8, and increased prostaglandin synthesis via inducible type 2 cyclooxygenase (COX-2). Progesterone maintains myometrial quiescence during pregnancy. In this study, we examined the effects of IL-1β and progesterone on IL-8 and prostaglandin E2 (PGE2) synthesis and IL-8 and COX-2 mRNA and promoter activity in amnion cells and lower segment fibroblast (LSF) cells. In both cell types, progesterone had no effect on basal IL-8 or PGE2 synthesis. In LSF cells, IL-1β significantly increased IL-8 and PGE2 synthesis and COX-2 and IL-8 mRNA expression, but progesterone significantly attenuated these effects. In prelabor amnion cells, IL-1β also increased IL-8 and PGE2 synthesis and both COX-2 and IL-8 mRNA and promoter expression; however, progesterone significantly attenuated these effects on IL-8 and PGE2 synthesis and COX-2 expression. In postlabor amnion cells, IL-1β increased IL-8 and PGE2 synthesis and COX-2 expression, but progesterone did not attenuate the effect of IL-1β upon IL-8 synthesis. Progesterone repression of IL-8 and COX-2 in LSF cells suggests that IL-8 and COX-2 have similar regulatory mechanisms in LSF cells and that progesterone may play a role in maintenance of cervical competence. The lack of effect of progesterone on IL-8 in postlabor cells may be the result of downregulation of the progesterone receptor during labor.

Reciprocal imprinting of human GRB10 in placental trophoblast and brain: evolutionary conservation of reversed allelic expression

Genomic imprinting may have evolved not only to regulate fetal growth and development, but also behaviour. The mouse Grb10 gene provides a remarkable model to explore this idea because it shows paternal expression in brain, whereas in the placenta and most other embryonic tissues, expression is from the maternal allele. To assess the biological relevance of this reciprocal pattern of imprinting, we explored its conservation in humans. As in mice, we find the human GRB10 gene to be paternally expressed in brain. Maternal allele-specific expression is conserved only in the placental villous trophoblasts, an essential part of the placenta involved in nutrient transfer. All other fetal tissues tested showed equal expression from both alleles. These data suggest that the maternal GRB10 expression in placenta is evolutionarily important, presumably in the control of fetal growth. As in the mouse, the maternal transcripts originate from several kilobases upstream of the imprinting control region (ICR) of the domain, from a promoter region at which we find no allelic chromatin differences. The brain-specific paternal expression from the ICR shows mechanistic similarities with the mouse as well. This conserved CpG island is DNA-methylated on the maternal allele and is marked on the paternal allele by developmentally regulated bivalent chromatin, with the presence of both H3 lysine-4 and H3 lysine-27 methylation. The strong conservation of the opposite allelic expression in placenta versus brain supports the hypothesis that GRB10 imprinting evolved to mediate diverse roles in mammalian growth and behaviour.

STOX1 is not imprinted and is not likely to be involved in preeclampsia

Previous studies showed that maternally inherited mutations in the STOX1 gene are responsible for pre-eclampsia. This is potentially of huge importance in the understanding of this disease. This study clearly showed that STOX1 is not imprinted and does not play such a role.

The effects of labor on maternal and fetal levels of insulin-like growth factor binding protein-1

OBJECTIVE Our purpose was to determine the effects of labor and fetal hypoxia on the levels of insulin-like growth factor binding protein-1 in the maternal and fetal circulation. STUDY DESIGN Serum levels of insulin-like growth factor binding protein-1 were determined in maternal and umbilical blood at delivery in two groups. The first group included 43 vaginal deliveries and 23 elective cesarean sections. The second group consisted of 44 women; in 24 the liquor was meconium stained and in 20 it was clear. RESULTS Levels of insulin-like growth factor binding protein-1 in the neonate were lower in deliveries occurring before onset of labor (p < 0.001), Mann-Whitney U test) and higher in cases with severe meconium staining (p = 0.01). There were no differences in maternal levels of insulin-like growth factor binding protein-1 between subjects in labor and not in labor or those with or without meconium staining. CONCLUSION The process of labor leads to an increase in fetal levels of insulin-like growth factor binding protein-1. This increase may well be associated with the relative fetal stress that occurs during labor. This suggestion is supported by the finding of the highest levels in labors in which there was thick staining of the liquor.

Superovulation, IGFBP-1 and birth weight

In this study, the effect of superovulation on the circulating levels of insulin-like growth factor binding protein-1 (IGFBP-1) has been investigated. IGFBP-1 levels were measured in singleton pregnancies achieved either naturally (n = 203) or following superovulation, in-vitro fertilisation and embryo transfer (IVF-ET) with either pituitary desensitisation with buserelin and superovulation with human menopausal gonadotrophin (b/hMG) followed by IVF-ET (n = 15) or with clomiphene citrate and hMG (CC/hMG) followed by IVF-ET (n = 15, 1st trimester only). The circulating levels of IGFBP-1 were similar in all three groups during the first trimester, and in both normal and b/hMG pregnancies in the second, but were significantly higher during the third trimester in b/hMG pregnancies than in normal pregnancies (P = 0.0002). The birth weights were significantly lower in the b/hMG group (P = 0.04), but not in the CC/hMG group compared with natural conceptions. Gestational age at delivery was similar in control and b/hMG pregnancies, but significantly reduced in CC/hMG pregnancies (P = 0.04). These data suggest that pregnancies achieved following superovulation with b/hMG are associated with elevated levels of IGFBP-1 during the third trimester of pregnancy and reduced birth weight.

IGFBP-1 in the placenta, membranes and fetal circulation: levels at term and preterm delivery

Samples of maternal blood, amniotic fluid, placenta, fetal membranes and umbilical venous blood were collected from 59 women at vaginal delivery (32-41 weeks gestation) and 15 women at delivery by Caesarean section (37-41 weeks gestation). Umbilical vein levels of IGFBP-1 were significantly lower in deliveries prior to the onset of labour (elective Caesarean section) than those during normal vaginal delivery. These levels were, in turn, significantly lower than those delivered by emergency Caesarean section. This difference was not seen in any of the other tissues examined. Concentrations of IGFBP-1 were lower in placenta and membrane extracts from preterm deliveries than in term deliveries. This difference was not observed in maternal or fetal serum or in amniotic fluid. This study confirms that the fetal membranes are a major source of IGFBP-1 and that fetal circulating levels are raised where there is evidence of fetal hypoxia. The absence of a comparable rise in levels in placenta, membranes or amniotic fluid suggests that the origin of this increase is from fetal tissue.

Detection of the tau protein in human serum by a sensitive four-electrode electrochemical biosensor

This study presents a novel approach based on a four-electrode electrochemical biosensor for the detection of tau protein - one of the possible markers for the prediction of Alzheimers disease (AD). The biosensor is based on the formation of stable antibody-antigen complexes on gold microband electrodes covered with a layer of a self-assembled monolayer and protein G. Antibodies were immobilized on the gold electrode surface in an optimal orientation by protein G interaction. Electrochemical impedance spectroscopy was used to analyze impedance change, which revealed a linear response with increasing tau concentrations. The assay is fast (<1h for incubation and measurement) and very sensitive. The limit of quantification for the full-length 2N4R tau protein is 0.03pM, a value unaltered when the assay was processed in bovine serum albumin or human serum. This technology could be adapted for the detection of other biomarkers to provide a multiple assay to identify AD progression in a point of care setting.

Elevated levels of insulin‐like growth factor binding protein‐1 in fetal distress

Objective To investigate the association between fetal distress (abnormal cardiotocograph tracing and/or a low fetal pH) and the levels of fetal IGFBP‐1.

Placental syndecan-1 and sulphated glycosaminoglycans are decreased in preeclampsia.

Abstract Glycosaminoglycans are found in extracellular matrix and on the cell surface in the form of proteoglycans. There is evidence that these molecules regulate biological processes, including cell survival, migration and angiogenesis. Preeclampsia is a common pregnancy disorder associated with insufficient placental development. This study aimed to determine the concentrations of glycosaminoglycans and the proteoglycan syndecan-1 within villous trophoblast and to investigate changes associated with preeclampsia. Seventy-five placental samples collected from third trimester singleton pregnancies were divided into term placentas following labour onset, gestational age-matched placentas prior to labour onset and preterm placentas. Preterm placentas were divided into three gestational age-matched groups, spontaneous preterm labour, preterm premature rupture of membranes (PPROM) and preterm preeclampsia. Sulphated glycosaminoglycan (sGAG) concentrations in placental extracts were quantified using a modified 1,9-dimethylmethylene blue assay. Syndecan-1 expression was localised using immunohistochemistry and concentrations in placental extracts determined by immunoassay. Preterm placentas had significantly lower sGAG concentrations compared to term tissues and concentrations were significantly lower in preeclampsia compared to spontaneous preterm labour (medians 5.80 and 10.0 μg/mg protein respectively, P<0.05). Syndecan-1 expression was localised to syncytiotrophoblast and median concentrations were lower in preeclampsia compared to PPROM material (preeclampsia median = 41.7, PPROM 74.4 ng/mg tissue) but not significantly different to concentrations in spontaneous preterm labour. Multivariate analysis revealed that decreased sGAG and syndecan-1 in preeclampsia were independent of labour, gestational age and birthweight centile. These findings may provide insights into a role for these molecules in the pathophysiology of preeclampsia.